[FFmpeg-cvslog] avcodec/mpeg4videodec: Check available data before reading custom matrix

[Michael Niedermayer]

ffmpeg | branch: release/2.7 | Michael Niedermayer <michael at niedermayer.cc> | Sun Nov 29 23:44:40 2015 +0100| [fc69fa8474ae2a3b3420074c17c908e0204c82af] | committer: Michael Niedermayer

avcodec/mpeg4videodec: Check available data before reading custom matrix

Fixes: out of array read
Fixes: 76c515fc3779d1b838667c61ea13ce92/asan_heap-oob_1fc0d07_8913_794a4629a264ebdb25b58d3a94ed1785.bit

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 891dc8f87536ac2ec695c70d081345224524ad99)

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=fc69fa8474ae2a3b3420074c17c908e0204c82af
---

 libavcodec/mpeg4videodec.c |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/libavcodec/mpeg4videodec.c b/libavcodec/mpeg4videodec.c
index e151f9e..dd2414b 100644
--- a/libavcodec/mpeg4videodec.c
+++ b/libavcodec/mpeg4videodec.c
@@ -1875,6 +1875,10 @@ static int decode_vol_header(Mpeg4DecContext *ctx, GetBitContext *gb)
                 int last = 0;
                 for (i = 0; i < 64; i++) {
                     int j;
+                    if (get_bits_left(gb) < 8) {
+                        av_log(s->avctx, AV_LOG_ERROR, "insufficient data for custom matrix\n");
+                        return AVERROR_INVALIDDATA;
+                    }
                     v = get_bits(gb, 8);
                     if (v == 0)
                         break;
@@ -1898,6 +1902,10 @@ static int decode_vol_header(Mpeg4DecContext *ctx, GetBitContext *gb)
                 int last = 0;
                 for (i = 0; i < 64; i++) {
                     int j;
+                    if (get_bits_left(gb) < 8) {
+                        av_log(s->avctx, AV_LOG_ERROR, "insufficient data for custom matrix\n");
+                        return AVERROR_INVALIDDATA;
+                    }
                     v = get_bits(gb, 8);
                     if (v == 0)
                         break;